Add a way to use shared CanonicalName root to deserialize Program.

pkg/front_end/lib/src/fasta/kernel/kernel_target.dart

Index: pkg/front_end/lib/src/fasta/kernel/kernel_target.dart
diff --git a/pkg/front_end/lib/src/fasta/kernel/kernel_target.dart b/pkg/front_end/lib/src/fasta/kernel/kernel_target.dart
index fbb3a9abfbda5ef5f0d55414f527837d4a10b32f..681b628757ee3a3b46da01179cc6ede8192de269 100644
--- a/pkg/front_end/lib/src/fasta/kernel/kernel_target.dart
+++ b/pkg/front_end/lib/src/fasta/kernel/kernel_target.dart
@@ -372,17 +372,16 @@ class KernelTarget extends TargetImplementation {
     Map<String, Source> uriToSource =
         new Map<String, Source>.from(this.uriToSource);
 
-    final Program binary = dillTarget.loader.program;
-    if (binary != null) {
-      libraries.addAll(binary.libraries);
-      uriToSource.addAll(binary.uriToSource);
-    }
+    libraries.addAll(dillTarget.loader.libraries);
 
     // TODO(ahe): Remove this line. Kernel seems to generate a default line map
     // that used when there's no fileUri on an element. Instead, ensure all
     // elements have a fileUri.
     uriToSource[""] = new Source(<int>[0], const <int>[]);
-    Program program = new Program(libraries, uriToSource);
+    Program program = new Program(
+        nameRoot: dillTarget.nameRoot,

[Siggi Cherem (dart-lang), 2017/05/12 16:27:57]

I think I don't have the full picture yet.

I'm currently wondering whether we want to put nameRoot in dillTarget or
somewhere else. Maybe it will help if you could tell me how do you intend to use
the nameRoot afterwards?

In the current CL it is used here while linking. If it's just going to be used
here, I'd be inclined to move the declaration right here in KernelTarget or
consider passing it as an optional argument to the linking function.

[scheglov, 2017/05/12 17:15:16]

Done.

+        libraries: libraries,
+        uriToSource: uriToSource);
     if (loader.first != null) {
       Builder builder = loader.first.lookup("main", -1, null);
       if (builder is KernelProcedureBuilder) {